Primer pump

ABSTRACT

A FUEL PRIMER PUMP ESPECIALLY ADAPTED FOR USE IN CONNECTION WITH INTERNAL COMBUSTION ENGINES FOR VEHICLES SUCH AS SNOWMOBILES AND THE LIKE. THE PRIMER PUMP INCLUDES A FUEL THROUGH THE PUMP TO ONE DIRECTION OF FLOW ONLY, AND FUEL THROUGH THE PUMP TO ONE DIRECTION OF FLOW ONLY, AND THE VALVE ELEMENT AND THE PUMP PLUNGER ARE ARRANGED SO THAT A PRESSURE DROP AT THE DISCHARGE END OF THE PUMP INDUCED BY OPERATING CONDITIONS OF THE INTERNAL COMBUSTION ENGINE WILL BE EFFECTIVE TO INDUCE UNDESIRED FLOW OF FUEL THROUGH THE PUMP TO FLOOD THE ENGINE.

May 23, W' E. TUPPER ET AL 3,664,774

PRIMER PUMP Filed May 5, 1970 JOHN R. HANSON www ATTORNEYS United StatesPatent O 3,664,774 PRIMER PUMP Willis E. 'Iupper and John R. Hanson,Dexter, Mich., assignors to Dexter Automatic Products C0., Inc., Dexter,Mich.

Filed May 5, 1970, Ser. No. 34,691 Int. Cl. F04b 21 02, 39/10 U.S. Cl.417-560 4 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF 'IHE INVENTIONThe present invention relates to an improved fuel primer pump adaptedparticulary, but not exclusively, for use with the fuel system of asnowmobile.

It is conventional practice to provide snowmobiles with small two-cyclegasoline engines for propulsion purposes, and it is normal practice toinclude in the fuel system a manually operable fuel primer pump toprovide enriched fuel mixtures for starting purposes and the like. Oneof the problems that arises in connection with the prior art fuelsystems is that when the engine is decelerated rapidly, it frequently isilood, and therefore stalls. This results from from an undesired ow offuel through the primer pump induced by the partial vacuum created atthe carburetor when the engine is suddenly decelerated. It is known toprovide check valves in the fuel system to overcome this problem, butsuch check 'valves are in general relatively complex, includingcompression spring and ball check elements, and they are not especiallysuitable in use, and are unnecessarily expensive.

SUMMARY OF THE INVENTION 'Ihe present invention has overcome theshortcomings of the prior art, and has provided an improved fuel primerpump which includes a relatively low cost unitary check valve elementwhich cooperates with the plunger of the primer pump to preventundesirable flooding of the engine.

According to one form of the present invention, a fuel primer pump isprovided comprising a pump housing including an internal pump chamberextending to one end of the housing. The end of the housing has aperipheral inlet passageway and a central outlet passageway, both incommunication with the pump chamber. An annular seat is provided at theinner end of the outlet passageway, and a resilient unitary valveelement is positioned in engagement with the annular seat. The valveelement has a tubular body portion fitted into the inner end of theoutlet passageway, and a duckbill portion forms an extension thereofhaving a pair of resilient lips extending from the end of the tubularbody portion further into the outlet passageway. The valve element alsoas a resilient umbrella portion extending annularly from the other endinto seating engagement with the annular seat and overlying the innerend of the inlet passageway. Thus, the duckbill portion and the umbrellaportion permit ow of fuel in one direction through the pump chamber, but

3,664,774 Patented May 23, 1972 prevent ow in the reverse direction. Apump plunger is mounted in the chamber in a normal position wherein itsend is adjacent to the annular seat urging the umbrella portion againstthe annular seat so as to prevent communication between the inlet andoutlet passageways. The pump plunger can be moved away from the valveelement to create a suction pressure in the chamber to induce flow offluid around the umbrella portion into the chamber, and on the reversemovement of the plunger the fluid in the chamber can be discharged outof the outlet passageway between the resilient lips of the duckbillportion. By virtue of this construction and arrangement, if theassociated internal combustion engine is decelerated rapidly, the lowpressure condition existing in the carburetor will be ineffective toinduce ow of fuel to the carburetor via the primer pump, because thepump plunger seated against the umbrella portion will serve to preventflow of fuel through the pump chamber.

Thus, it is an object of the present invention to provide an improvedprimer pump for use with internal combustion engines.

Other objects of this invention will appear in the following descriptionand appended claims, reference being had to the accompanying drawingforming a part of this speciiication wherein like reference charactersdesignate corresponding parts in the several views.

BRIEF DESCRIPTION OF THE DRAWING FIG. l illustrates partially inlongitudinal section a primer pump embodying the present invention, andillustrates schematically a portion of the fuel system with which theprimer pump is used;

FIG. 2 is a fragmentary view showing the action of the valve element ofthe pump when the pump plunger is moi/ed in one direction away from itsnormal position; an

FIG. 3 is a view similar to FIG. 2, but illustrating the action of thevalve element when the pump plunger is moved in the opposite directiontoward its normal position.

DESCRIPTION OF THE PREFERRED EMBODIMENT Before explaining the persentinvention in detail, it is to be understood that the infvention is notlimited in its application to the details of construction andarrangement of parts illustrated in the accompanying drawing, since theinvention is capable of other embodiments and of being practiced orcarried out in various ways. Also, it is to be understood that thephraseology or terminology employed herein is for the purpose ofdescription and not of limitation.

Referring now to the drawing, the invention will be described in greaterdetail. As there shown, the fuel primer pump 10 is mounted in a panel 12and is connected as part of a fuel system 14. The latter includes agasoline tank 116 a carburetor 18, a main fuel line 20 extending fromthe gasoline tank 16 to the carburetor 18, a supply line 22"incommunication with the gasoline tank 16 via the line 20 and connected atthe other end to the fuel inlet .tting 24 of the primer pump 10. A fueloutlet fitting 26 is connected to the fuel line 28 which communicateswith the carburetor 18 in a conventional manner to permit theintroduction of a desired enriched mixture of fuel to the associatedinternal combustion engine (not shown).

The pump primer 10 has a pump housing 30 which includes the cylinderportion 32 and the header or cap portion 34. The header or cap portion34 closes the one end of the cylinder portion 32 and includes aperipheral inlet passageway 36 and a central outlet passageway 3-8, bothof which are in communication with the internal chamber 40 definedwithin the housing 30. A pump plunger 42 including the piston portion44, the rod portion 46 and the handle portion 48 is mounted so that therod portion extends from the other end of the housing 30 and the pistonportion is in sealing engagement with the internal bore of the housing30, by means of the sealing or Oi-ring 50. A compression spring 52 isoperatively positloned between the piston portion 44 and the other endof the housing 30 so as to urge the plunger to the one end of thehousing 30, as is shown in lFIG. l.

The inner end of the outlet passageway 38 formed in the header member 34defines an inwardly facing annular seat 54, and a resilient unitaryvalve element 5-6 is seated on the inner face of the annular seat. Thevalve element 56 includes a central portion 58 which extends into theoutlet passageway 38 and is interlocked with the annular shoulder 60 ofthe passageway so as to prevent axial displacement of the valve elementin the passageway 38. The valve element 38 includes the duckbill portion62 which has a pair of resilient lips 64 forming extensions of thecylinder portion 58, and they are adapted to permit flow of fuel out ofthe passageway 58 as shown in FIG. 3, and to check ow of fuel in thereverse direction. The valve element 38 also has an umbrella portion 66which is seated on the inner face of the annular seat 54 and whichoverlies the inlet passageway 36 and the annular passageway 68 incommunication with inlet passageway 36.

By virtue of this arrangement, when the plunger 42 is manually movedtoward the other end of the housing 30, the umbrella portion 66 will befree to deflect to the position shown in FIG. 2 to permit fuel to enterthrough the inlet fitting 24 and to ow through the inlet passageway 36to the interior of the chamber l40. Thereafter, when the plunger ismoved toward the other end, as indicated in FIG. 3, the umbrella portionwill be returned to a position shown in PIG. 3, preventing return flowof fuel through passageway 38, but the lips 64 of the duckbill portion62 will then separate to permit discharge of the fuel through the outletpassageway 38 and the litting 26. When the pump plunger 42 is in itsnormal position shown in FIG. 1 wherein it is adjacent to the annularseat 54 and is urged against the umbrella portion 66, it will preventcommunication between the inlet and outlet passageways 36 and 38,thereby preventing flow of fuel from the pump during such time when apressure drop or partial vacuum is created in the carburetor. Thus,undesired ooding of the engine which will cause stalling is prevented.This is accomplished by a relatively simple primer pump which includes asimple, trouble free and relatively low cost check valve element.

It is claimed:

1. A primer pump comprising a pump housing providing an internal chamberextending to one end of the housing, said one end deiining a peripheralinlet passageway and a central outlet passageway in communication withsaid chamber and an annular seat at the inner end of the outletpassageway, a resilient unitary valve element positioned in engagementwith said annular seat, said valve element having a tubular body portionextending into the inner end of said outlet passageway, a duckbillportion having a pair of resilient lips extending from one end of saidtubular body portion further into said outlet passageway and a resilientumbrella portion extending annularly from the other end of said tubularbody portion with its inner periphery in seating engagement with saidannular seat and its outer periphery extending over the inner end ofsaid inlet passageway, and a pump plunger in said chamber in a normalposition wherein its end is adjacent to said annular seat pressing saidumbrella portion against said annular seat so as to preventcommunication between said inlet and outlet passageways, said pumpplunger being responsive to an applied force in one direction to moveaway from said valve element to create a pressure drop in said chamberat said inlet passageway to induce flow of fluid around said umbrellaportion into said chamber and being responsive of an applied force inthe other direction to return to said normal position to discharge thefluid in said chamber between said resilient lips and through saidoutlet passageway.

2. The primer pump that is delined in claim f1, wherein said tubularbody portion and said outlet passageway have cooperating means retainingsaid tubular body portion against axial displacement in said outletpassageway.

3. The primer pump that is defined in claim f1, wherein said pumpplunger includes a rod projecting from the other end of said housing formanually applying said force to move the pump plunger away from saidvalve element.

4. The primer pump that is defined in claim 3, wherein a compressionspring is mounted between said other end and said plunger for applyingsaid force in the other direction to return said plunger to its normalposition.

References Cited UNITED STATES PATENTS 3,527,551 9/1970 Kutik et al417-571 X 2,424,595 7/1947 Warren 417-571 X 3,159,176 l2/1964 Russell etal. 137-493.l

FOREIGN PATENTS 560,076 3/ 1957 Italy 417-560 875,142 4/ 1953 Germany417--479 `CARLTON R. CROYLE, Primary Examiner R. E. GLUCK, AssistantExaminer U.S. Cl. X.R.

